A great product for all arcane classes. 5 highly flavored cultures, which can integrate all arcane classes from the PHB 1 and 2. The fluff is really good, the book is very well organized and it is easy to read, even on screen.

My only concerns are on the mechanics side. I didn't see any major balance issue, yet I feel there is something missing. I expected more powers, and a few paragon path as well. On the alternative class features, some of them were quite interesting, but others are less attracting (not from a lack of balance, though).

Need more background for your wizards or a cool place for them visit? Then this is the book for you. Living in a world full of magic should make for some magical lands and people, Arcane Flavor present five such cultures. Easily added to any campaign world. Each city, culture or locale also comes with new powers, spells, feats or rituals that are common to that region (and no where else!)
Cailleath is a fey city like no other. It's people are a strange assortment for any world and getting stranger all the time! It is a magic cosmopolitan filled with wonders not possible anywhere else in the world, or worlds, given it's nature.
The Valok are nomadic peoples with their own stories and songs and these contain power.
The Merry-Bedlam Company stretches this idea even further with a large extended theater family whose original race is no longer clear.
Karxal is a arid nightmare of a land, all the more reason to find arcanists devoted to beauty.
And finally to strike fear into hearts of power mad wizards everywhere are The Ternion.

The product has good layout and everything is very clear to read. The art is also good.

The rules are 4th Edition, but there is enough background here that it would be good for any game.